dts: psoc6: move pinctrl subdevices up a node

Refactor the pinctrl nodes slightly so that the port devices are not
child of the main pinctrl node. This is because the pinctrl node is
being used as parent for pinctrl setting nodes itself, and having the
port nodes as child end up creating a circular depdency with the edt
child enumeration patch.

Signed-off-by: Fabio Baltieri <fabiobaltieri@google.com>